In aircraft, in particular aeroplanes, wireless radio-linked transmission systems are increasingly being used, and provide communication within the aeroplane during flight or when the aeroplane is located on the ground. The communication partners are passengers or crew members, who are located for example in the passenger cabin of the aeroplane. During the flight, the passengers wish to use various data services, in which data have to be transmitted, by means of their portable terminals, such as laptops, smartphones, mobile radio devices or PDAs. In this context, the users' end devices transmit data via a radio interface and a transmitting and receiving antenna, which is provided in the passenger cabin, to a transmission system of the aeroplane, which is connected to a base station during flight by means of a satellite connection for example. Data are transmitted via the air interface between the transmitting and receiving antenna of the passenger cabin and the terminals by means of radiofrequency signals in predetermined radiofrequency bands. For example, for providing WLAN services, radiofrequency signals are transmitted or received in predetermined WLAN frequency bands.
Since the available frequency spectrum is limited, radiofrequency bands for different services are increasingly being arranged packed tightly together, and in many cases no distinct guard bands or protective frequency bands are provided between the various radiofrequency bands.
In an aeroplane, it is useful for the radiofrequency signals, which are transmitted in different radiofrequency bands which in some cases are very close to one another, to be brought together to a shared transmitting and receiving antenna which is provided or laid in the passenger cabin.